Difference between revisions of "Some specifications on PMTs"
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: (counter with ~20 MeV) | : (counter with ~20 MeV) | ||
* The rate is about 4 times larger for the last counter (at 3 GeV) | * The rate is about 4 times larger for the last counter (at 3 GeV) | ||
| + | |||
| + | ''' Operating gain ''' | ||
| + | * Assume 4 MHz counter rate, 400 p.e., 50 &mA anode current | ||
| + | * The maximum anode current is typically 100 &mA. We have to operate the tubes at least 2 times smaller current. | ||
Revision as of 15:59, 14 September 2012
Light yield estimates
- 5 mm thick scintillators
- 10000 initial photons per tagged electron
- assume that 2000 photons are collected (20 % light collection efficiency)
- 400 p.e. (assuming 20% quantum efficiency)
Counter rates (according to the latest Dan's design)
- 1.1 μ A electron current,
radiator
- (corresponds to the photon flux of
phot/sec in the cohrent peak region)
- Counter rate around E_gamma = 9 GeV: 1 - 1.5 MHz
- (counter with ~20 MeV)
- The rate is about 4 times larger for the last counter (at 3 GeV)
Operating gain
- Assume 4 MHz counter rate, 400 p.e., 50 &mA anode current
- The maximum anode current is typically 100 &mA. We have to operate the tubes at least 2 times smaller current.
